As the subject says, I dropped my raspberry pi on the floor.
It happened about a week ago.
It was in a plastic case, and nothing seems to be broken... but the CPU seems to be easier overloaded.
Do you think the CPU could be damaged? How could I find out if it was?
I don't know if it's just me, or if the CPU really is damaged.

For two reasons.
Firstly, adding more software that runs as daemons taking their share of memory and CPU, increased paging.
Secondly, the perceived slow down that a user feels after going back to a slow computer after using another faster zippier one.
Neither scenario is unusual.

Of course if you set more processes running on your machine they take computer power, performance has to come from somewhere. Something else has to be slowed down. You can't fight the laws of physics.

And I guess one forgets how slow a machine is after using a faster one for a while.

One could also imagine that ones databases get slower to index and slower to access as they grow bigger.

And so on. Some what obvious and very much dependant on the applications a use sets running on his machine. Performance analysis will depend on the applications in use, tuning that performance may be trivial or complex. For example optimizing database performance may not be easy and may depend heavily on the patterns of usage.

That is all far from some nebulous statement that "computer to appear to run slower over time".

I wonder if this is the inverse of "Moore's Law" that the peception of any given RPi's speed halves every year and a half

Given the subjective nature of percieved speed maybe there is some relatavistic component to the inverse that may change the time element of the inverse of "Moore's Law".

The advantage you have with a RPi is you can build your RPi to do one dedicated task and swap out the SD card when you change task, this would stop an accumulation of background demons. Or a more drastic option a re-image

Of course we now have multiple generations and models of RPi as well as flavours and Build's of Linux.

All of these variations can lead to different perceptions of speed.

Noob is not derogatory the noob is just the lower end of the noob--geek spectrum being a noob is just your first step towards being an uber-geek

If you find a solution please post it in the wiki the forum dies too quick

We should get back on-topic now. Has the OP tried building a new SDCard? Has the OP done a visual inspection of the board looking for borken components? Does it do anything exciting with the SDCard out and the power connected?

Note: Having anything remotely humorous in your signature is completely banned on this forum.